In the quest to stop chirping gave the exhaust manifold a nip, and whipped off a carb to try a new gasket.. Looked promising in that the light smear of Curil on the gasket appeared missing on the bottom edge.. There's a likely place for air to whistle through I thought then I took a picture down the inlet to make sure nothing in there. Nothing apart from a crack in the head!.. Are inlet cracks there a worry and need to replace head or all fine and thrash the life out of it?... And do I need a written permit from mods to post lots of swear words if its buy a new head (prob 2 as it's a 1800 big valve version ) Sent from my SM-T580 using Tapatalk
That one is big enough to allow the valve seat to loosen. I dont think I could go further with that head, all the cracks I had in cylinder heads were shallow and didnt come round the back of the valve seat like that. The exhaust valve seat next to it is probably also in a precarious position.
There were casting Mark's on the other side.. but cant find photos of there... I'll have another look tomorrow when I've stopped sulking.. Sent from my SM-T580 using Tapatalk
I have a head with the same marks in the same place on both ports. I thought the coincidence was too much and looking closer they look like casting marks. I’ll look again today and take some pics if it would help you make a decision ?
Yes please.. Mrs Deefer is threatening to inspect my crack later .. shes got little fingers... before she goes looking at bridges later, she likes metalwork.
Deefer66, I hope this gives you some peace of mind. The photos show the casting marks from inlet side to the valve seats, as you can see these were crack detected.
Yes that one has been there for a while, although ive never measured it just photos, its still in the line of the casting flashing marks
I meant generally. The seat could do with the sharp overhanging edge blending into the port. Below that is another hard edge that softening would improve flow. That with a better seat cut and unshrouding the inlet valves are the sure fire /biggest gains as I understand it. Are they new seats?
Casting marks for the win! Cheers @Gnasha Just had more of a look And a v short film.. Mrs D's little fingers can feel the change in profile at this point so 99% casting Setting up backfire though the carb seems to have made the gap for the chirp too So quick clean up, new EMPI gasket.. bit of a reduction in footprint to make it fit easier and get it back together if to the rain stops.. Thanks all Sent from my SM-G930F using Tapatalk
Those casting flashes should be blended into the port to avoid stress risers. Remove as little material as possible but smooth the whole port without polishing it or changing the shape - unless you know what you are doing.